All zones in the kingdom have a 'water depth', which among other things effect wandering monster.

At depth 6 in each of the three zone types (indoor, outdoor, basement), the wandering monster that shows up gives an item that can be used to get a skill. There are three sets of 7 skills in Heavy rain. For Thunder, Rain, and Lightning.

*edit* It looks like there is some mechanic which lets you aquire some skills in later runs. So the requirement/timing of getting skills won't actually be as strict of an issue later on...

You need the +1 depth buff from Thunder skills to get Rain skills.
You need the +1 depth buff from Rain skills, And the previous Thunder skill to get Lightning skills

The earliest you can see 6th depth basement is Hobo Sewers (basement) or Crypt.
The earliest you can see 6th depth indoor is 2nd floor spooky raven with Thunder Cloud Buff.
Once you get both the Rain and Thunder Buff, you can probably see depth 6 outdoor at goat, airship, level 9 quest.

You can expect to hit your wandering monsters on turn 9-11, 44-56, 79-101 for the first three. I've found a 34 turn timer to be relatively reliable for the start of the 'window'. Meaning if you want the skills you'd have to survive sewers at turn 10, and unlock spooky raven before your 2nd or 3rd.

You seem to get 7 rain back (about?) every 7 adventures, so the 50 rain "Rain Man" fax means you get a lot of faxes this path. I didn't manage to my first rain skill around turn 130 something, but at that point I had 100/100 rain, so maybe it starts full, or you start accumulating rain from the start of the run?

Anyone have bright ideas about what to fax other than the usual suspects?
-Ninja assassin (ninja gear might wash away, but you have some flexibility to fax another)
-Lobsterfrogman
-writing desk if you can get to 5 copies to skip the first floor
-Mountain Men
-Screambat if your sonar washes away?
-War outfit(s) (Frat Boy Spy, War Hippy Spy don't need YRs, maybe more for Softcore where you can pull pieces that wash away)
-Bandit for nuns trick
-Quantum mechanic
-Fish for DNA lab? (Although at least one of the indoor wandering monsters is a fish, the Freshwater Bonefish)

The rain +depth skill seems to be +2 depth. I used my starting aquaconda brain to grab that skill to make it more feasible to get other skills, and I started with 100 rain. One adv in the outskirts without the buff was Depth 1 as expected, and then activating the buff made it Depth 3.

The thunder rolls! And the lightning strikes! But instead of fading in a microsecond, the lightning grows, crashes together, and takes on a familiar form. The next clap of thunder sounds suspiciously like, "MOOOOO," and before you stands a fearsome lightning-wrought bovine: a storm cow!
What? You've never heard of a storm cow? Man, what are they teaching kids in schools these days? Where did you think lightning milk came from?

What? You've never heard of lightning milk?

It gets the jump on you.

The storm cow gores you through the heart, draining your energy and your blood in equal measure.

Bowling balls - first run I lost 8 to the flood, but this run with the whiskers active I only lost 1
White Pixels - first run I lost a handful, but this run with the whiskers and umbrella lowering depth to 1 I didn't lose any.
Tomb Ratchets - first run I lost many, but this run with the whiskers and umbrella lowering depth to 4 (I think?) I didn't lose any of the 8 I needed.